Students who take a college level introductory astronomy lab course for non-science majors answer survey questions about the Moon and its phases as part of a regular curriculum. We analyze responses to these questions to determine student ideas about the phases of the Moon and whether or not there is any pattern to these ideas. In addition, we look at the effects of changes to an astronomy lab lesson that incorporate a real three-dimensional (3D) model of the Sun/Earth/Moon system to determine whether or not the use of a real 3D model affects student ideas about the Moon and its phases. Our hypothesis is that there is a relationship between the concept that the phases of the Moon are caused by Earth's shadow and the concept that the Moon is more apt to be up at night than during the day. We also propose that the 3D model will assist students in obtaining correct conceptions about the Moon. Results from the study show that college-level students possess unscientific ideas about the cause of the phases of the Moon and that a large percentage of these students believe the Moon is only up at night. Students' ideas about the phases did not show any relationship to their ideas about when one is most likely to observe the Moon whether it is night or day. Use of the 3D model did not have an effect on students gaining scientific concepts about the Moon and its phases.